How to tell if you're eligible for AT&T's iPhone 4 upgrade pricing

Any AT&T customer whose upgrade date occurs before the end of 2010 will be eligible to buy Apple's new iPhone 4 at the $199 and $299 subsidized pricing up to six months early, with a new two-year contract.

The exclusive wireless carrier of the iPhone in the U.S. said that the important date for customers is their current "upgrade date" —not when their contract expires. The distinction is better for customers, as most are upgrade-eligible before their contract is over.

"Any existing iPhone customer eligible for an upgrade between today and the end of this year will be eligible for our best pricing for iPhone 4, $199 and $299, with a two year term commitment," the company said Monday.

AT&T customers can verify their upgrade eligibility by going to att.com/iphone, or by dialing *639#. AT&T said its upgrade tools reflect the new timeframe. The new iPhone goes on sale June 24 for $299 for 32GB and $199 for 16GB, and preorders will be taken on June 15.

"With our early upgrade policy and new, more affordable wireless data plans, we're expanding the market for iPhone 4," AT&T said. "We're making our best pricing immediately available to current iPhone customers eligible for an upgrade anytime this year. And we created new, more affordable data plans so that more people could experience the benefits of the mobile Internet.

"Individual iPhone voice and data plans now start at just $54.99 per month (was previously $69.99) and FamilyTalk voice and data plans with two iPhones start at just $89.99 per month (was $119.99). Our data plans all include unlimited usage at more than 20,000 AT&T Wi-Fi Hot Spots in the U.S."

Though U.S. iPhone customers must sign a two-year contract with AT&T in order to receive the iPhone at a subsidized price, the wireless carrier frequently offers faster upgrades for its highest paying customers. Those with more services and a higher monthly bill typically are not required to wait the full two years before they become eligible. AT&T previously revealed that generally speaking, customers who spend more than $99-a-month per line are eligible for an upgrade between 12 and 18 months into their contract.

"We want to help customers upgrade to a new device as quickly as possible  exact timing can depend on several factors unique to each account (length of contract, payment history, etc.)," a company spokesperson said Monday.

No commitment pricing is also available for Apple's handsets. While they do not require a two-year term commitment, both voice and data service is necessary to buy an iPhone 4 or iPhone 3GS.

Apple and AT&T's new pricing for the iPhone 4 and iPhone 3GS, without taxes and fees, is as follows: